1. Field of the Invention
The present invention relates to a foldable wheelchair.
2. Description of the Related Art
A wheelchair shown in FIG. 10 is known which can be folded by moving right and left side frames 101 toward each other. The both side frames 101 of the known wheelchair are coupled to each other by X-link portions 121. The X-link portions 121 make the wheelchair foldable.
Each of the X-link portions 121 of the wheelchair shown in FIG. 10 includes a pair of link rods 122. The link rods 122 intersect each other in their central parts. The link rods 122 are rotably coupled by a pivot shaft to each other at the intersection 133 of the link rods 122. The lower ends of the each of the link rods 122 are swingably coupled to bottom frame portions 111 of the side frame 101 by pivot shafts. The upper ends of each of the link rods 122 are coupled to seat frames 106. A flexible seat 107 is coupled to the seat frames 106, which is coupled to the upper ends of the link rods 122. When the wheelchair is unfolded, the both side frames 101 are moved away from each other so that the upper ends of the link rods 122 are moved away from each other. As a result, the flexible seat 107 can be held under tension whereby forming a seat 105 which can support the wheelchair user. When the wheelchair is folded, the both side frames are moved toward each other, and the link rods 122 of the X-link portion 121 pivot so that the upper and lower ends of the link rods 122 are moved toward each other. As a result, the wheelchair can be folded.
The present applicant has been developed a wheelchair which can have a reduced width and be compactly stored when the wheelchair is folded by moving its both side frames toward each other (see International Publication No. WO 2007/007,811). FIG. 11 is a front view showing the wheelchair when unfolded. FIG. 12 is a front view showing the wheelchair shown in FIG. 11 when folded by moving its both side frames 201 toward each other. In the wheelchair shown in FIGS. 11 and 12, the central parts of link rods 222 of each of X-link portions 221 are curved. In the wheelchair of FIG. 12, when the both side frames 201 are moved toward each other, the seat frames 207 and the upper and lower ends of the X-link portions 221 are positioned on the interior side of the side frames 201. According to this arrangement, the width of the folded wheelchair can be small.
In the wheelchair shown in FIG. 12, when the X-link portions 221 are folded, the space on the both sides of the link rods 222 at the intersection 233 is reduced by the curved link rods 222. The illustrated wheelchair includes middle frames 215 which are arranged on the both sides of the intersection 233 of the link rods 222. If the side frames 201 are arranged too close to each other, the middle frames 215 will contact the link rods 222, and the movement of the middle frames 215 or the link rods 222 may be restricted. In other words, when the wheelchair is folded by moving the side frames 201 toward each other, the size reduction in the width direction of the wheelchair is limited by the curved link rods 222.
The present invention is devised to solve the above problem. It is one object of the present invention to provide a wheelchair which has a further reduced width when folded by moving its side frames toward each other, and can be more compactly stored.